The present invention relates to an automobile cell and a related method and, more particularly, to a flat type automobile cell and its related method wherein use is made for a laminate film, compositely made from a polymer and a metal, as a cell outer sheath to provide an optimum structure for application to a drive source for a motor of an electric vehicle, a hybrid vehicle or a fuel cell-powered vehicle, or for application to a storage battery thereof.
In recent years, among increasing trends in which environmental protection movements and air pollutions caused by exhaust gases of automobiles attract public attention worldwide, research and development works have heretofore been ardently made to provide an electric vehicle (EV) powered by a power source energized by an electricity, a hybrid vehicle (HEV) adapted to travel in combination with an engine and a motor and a fuel cell powered vehicle (FCV) powered by a prime power source energized by a fuel cell.
Thus, it is said that the research and development works for cells available to be installed on such vehicles and each having a high energy density and high power output progressively share a further important role in industrial fields.
As the cells for such applications, it is a general practice to use a secondary cell available to achieve repeated operations in charging and discharging cycles. The cell is comprised of a structure wherein a wound electric power generating element is accommodated in a cylindrical type outer sheath case and a structure wherein the wound electric power generating element or an electric power generating element, in which planar plate shaped electrode and separators are stacked, are accommodated in a flat type outer sheath case.
Because of an adequate strength required in the cylindrical type or the flat type outer sheath case, Japanese Patent Application Laid-Open Publication No. 2000-348772 discloses a structure that employs an outer sheath case made of metallic vessel.
Further, in order for the cell to have a light weight while ensuring a high energy density and high power output, Japanese Patent Application Laid-Open Publication No. 11-224652 discloses a gas-tightly sealed structure wherein a laminate film is used as an outer sheath case with circumferentially peripheral portions thereof being thermally welded to providing a sealing effect.